Electrical contact cleaner composition



United States Patent 3,421,872 ELECTRICAL CONTACT CLEANER COMPOSITIONClarence Harry Anglin, 1122 Corn Tassel Trail, Martinsville, Va. 24112No Drawing. Filed Oct. 19, 1965, Ser. No. 498,102 US. Cl. 51-304 2.Claims Int. Cl. C09g 1/02 ABSTRACT OF THE DISCLOSURE A cleaning andpolishing composition for electrical contacts and the like comprised ofa mixture of powdered graphite, pumice and bodied grease of selectedviscosity.

This invention relates to an electrical contact cleaner composition andmore specifically to a method and composition for reducing theelectrical resistance of electrical contacts, switches, controls,television tuner contacts and the like.

It is well known that the flow of current through electrical contactsproduces oxidation and other deleterious effects upon the surface of thecontacts particularly when the contacts are opened and closed duringrepeated operations. Certain contacts are known to acquire heavierdepositions of oxides and other foreign matter than other contacts, theamount of deposition being determined by the magnitude of the current,the voltage, and the inductive or capacitive effects of the apparatus incircuit with the contacts. As repeated operations cause the depositionsto build up upon the surface of the contacts, the impedance across thecontacts may increase to a value wherein the apparatus in circuit withthe contacts becomes inoperative or at least performs at a greatlyreduced efficiency. A particular environment in which electrical contactresistance may prove to be highly undesirable is in the television tunerincorporated as part of the circuitry in the well-known televisionreceiver. In tuner contacts of this and other types, a plurality ofrotary contacts are caused to engage a plurality of stationary contactseach time the channel selector is rotated. Accordingly, it becomes analmost hopeless undertaking to remove the foreign deposits acquired bythe many contacts by conventional means.

Heretofore, it has been the common practice to manually remove theforeign deposits from the contacts through the utilization of a sharpinstrument or other device by scraping the contacts to free the foreignmatter and thereby reduce the contact resistance and thus attempt toprovide substantially zero resistance across the contacts. This,however, is a hit-or-miss approach in that the contacts themselves maybe damaged during the manual removal process so that the contactscontinue to register a high impedance to current flow.

Other means are known which have achieved a small degree of success forremoving the foreign matter deposited upon electrical contacts, such asthe application of carbon tetrachloride to the contacts. However, thisprocedure has been found to be highly unsatisfactory in that once thesolution has been applied to the contacts, the contacts immediatelycontinue to build up deposits upon subsequent operations.

Accordingly, it becomes highly desirable that a method and compositionbe found which will alleviate the foregoing problems and at the sametime continue to maintain the contacts in a zero resistance statethroughout normal operations.

Accordingly, it is the principal object of the present invention toimprove the operation of current carrying contacts.

It is a further object of the present invention to reduce the contactresistance of electrical contacts.

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It is a still further object of the present invention to provide amethod and composition for improving the operation of current carryingcontacts such as those found in television tuners and the like.

It is a still further object of the present invention to provide amethod and composition for improving the operation of current carryingcontacts by once reducing the electrical contact resistance thereof andsubsequently maintaining the contacts at a minimum contact resistancethroughout their life in normal operation.

The present invention relates to a composition of graphite, pumice andgrease which when applied to the contacts will clean the contacts uponsubsequent engagement and disengagement of the contacts. The compositiondoes not flow at the usual temperatures encountered so that it remainsfor continuous subsequent cleaning operations. Further, the method ofemploying the novel composition for reducing the contact resistance isalso envisioned.

In the novel composition herein set forth, graphite of a suitable gradesuch as micro-fine is mixed with powdered pumice and grease. The greasemay be one such as a conventional lubricant mineral oil thickened by 5%to 40% inorganic gels such as silica gel, clays or the like, or a greasecompounded of oils plus 5% to 40% fatty acid soaps such as sodium,potassium, etc. The grease is viscous and will not flow at the ordinaryambient temperatures encountered.

A formula for a composition such as that set forth made in accordancewith the principles of the present invention and establishing the rangeof the constituents is as follows:

I Constituent: Percentage by weight Graphite 2-8 Pumice 25-40 Grease 4060 It will be readily understood that the above formula may be variedappreciably. The graphite is employed as a cleaning and conductingagent; the pumice acts as a polishing and gelling agent; and, the greaseserves as a lubricant and gelling agent. The three ingredients are mixedtogether thoroughly in a mixer and packaged in suitable dispensing typetubes or other containers.

Although the foregoing formula establishes the range of theconstituents, perhaps the preferred formula would be as follows:

Constituent: Percentage by weight (approx) Graphite 6 Pumice 34 Grease60 After the composition has been thoroughly mixed, and packaged in asuitable container, it is now ready for use. As an illustrativeembodiment of the method for utilizing the composition, the cleaning ofthe contacts of a television tuner is selected since tuner contactsbeing large in number, are highly susceptible to foreign deposits and assuch, the foreign deposits quickly produce malfunctions and oscillationof the sensitive circuits coupled thereto. Although the cleaning oftelevision tuner contacts has been selected as an illustrativeembodiment, it will be readily apparent to those skilled in the art asto the practice of the invention wherein other contacts, switches,controls, etc. are to be cleaned.

A small quantity of the composition is applied to a row of the tunercontacts when a standard coil tuner is to be employed and to the waferdisk when arotary disk type tuner is used. Next, the channel selector isrotated approximately so that a wiping action is effected between themovable and stationary contacts. Next, the channel selector may berotated in the opposite direction to complete or at least commence thecleaning method. Alternately, a small quantity of the composition mayagain be applied to the contacts after the first rotation of the channelselector followed by rotation of the channel selector in the oppositedirection. The rotation of the channel selector which produces rotationof the contacts in both directions deposits the cleaning, polishing andlubricating composition on the main contacts. Due to the gelling actionof the pumice and grease and also due to the high heat resistance of thegrease, the composition will remain on the main contacts and willcontinue to clean, polish and lubricate the contacts each time thecontacts are rotated. In normal operation, no further applications ofthe composition are required since as set forth, the composition remainson the contacts and continues to cause the contact resistance to remainat substantially zero.

Thus, the present invention may be embodied in other specific formswithout departing from the spirit and the essential characteristics ofthe invention. The present embodiment is, therefore, to be considered inall respects as illustrative and the scope of the invention beingindicated by the appended claims rather than the foregoing description,and all changes which come within the meaning and range of theequivalency of the claims are, therefore, intended to be embracedtherein.

I claim:

1. An electrical contact cleaner composition comprising a viscousmixture of powdered graphite in a weight range of about 2% to 8%,powdered pumice in a weight range of about 25% to 40%, and bodied greasein a weight range of about 40% to 60%, said composition being nonfluentat ambient atmospheric temperatures.

ZfAn electrical contact cleaner composition comprising a viscous mixtureof about 6% by weight of powdered graphite, about 34% by weight ofpowdered pumice, and about 60% by weight of bodied grease, saidcomposition being non-fluent at ambient atmospheric temperatures.

References Cited UNITED STATES PATENTS 1,003,983 9/1911 Callahan 51--3041,195,246 8/1916 McCormick 51-295 2,185,262 1/1940 Lupo 51-304 2,417,8003/1947 Weisser 51-304 2,649,362 8/1953 Fowler 51304 DONALD J. ARNOLD,Primary Examiner.

US. Cl. X.R.

